A power saving type information processing apparatus is provided which is not expensive and can provide a high interruption performance without using an expensive and dedicated memory and a complicated software process. After an SDRAM setting register of an SDRAM controller outputs a SELF allowance signal for allowing SDRAM to transfer to a power saving mode from a normal operation mode, a WAITI command fetch detecting circuit outputs a WAITI command detecting signal. In this case, SDRAM is made to transfer to the power saving mode. If a CPU detects an external interruption while SDRAM is in the power saving mode, SDRAM is returned to the normal operation mode irrespective of settings of the SDRAM setting register.